The present invention concerns a method for programming the shattering of projectiles at a shattering point in the neighborhood of a target, and a tube weapon with a programming system carrying out the shattering program. The priority of Swiss Patent Application No. 2003 0298/03 of Feb. 26, 2003 is claimed and the Application is incorporated herein.
In connection with the invention the term tube weapon is to be understood to include such tube weapons which are suited to the launching of projectiles, especially grenades, whose trajectories are strongly curved and which preferably lie in the lower angle group. The angles of descent of the projectiles which are launched by such tube weapons in the context of the invention lie in a range which is larger than about 5°. Such tube weapons are used in general for destruction of land and sea targets.
To obtain a maximum weapon effect with a shatterable projectile, the shattering of the projectile must take place in the nearby space surrounding the target to be destroyed. So that this happens, projectiles with programmable ignition are used, which in general are referred to as programmable or fuse settable projectiles. The goal of the programming is to achieve with similar projectiles, which are launched with similar elevations and which thereby fly along basically the same trajectory, detonation at different shattering points according to the position of the target with respect to the tube weapon.
Customarily in the programming the projectiles are not so directly programmed that they detonate at a given shattering point. More often the time of the shattering or the flight duration of the projectile between the weapon and the shattering point is programmed. For this either the flight duration can be directly programmed, or the number of projectile rotations up to detonation is pre-set.
So that the projectile develops an optimal effect several conditions in regard to the shattering point must be observed. The shattering of the projectile should take place at an optimal distance in reference to the target. The basis of this is the following: in the shattering or detonation of such projectiles numerous fragments or splinters are formed. These splinters in general have only a small mass but a high initial speed. Of course this speed diminishes rapidly because of air resistance. The splinters move outwardly from the detonation point, into a splinter space, which for example can be referred to as a scatter cone. The effectiveness of the splinters is essentially a function of their mass, their materials, and their shape as well their speed at the target. This effect diminishes with diminishing speed, or in other words, with increasing distance from the shattering point. The spatial effective region of such grenades or projectiles with explosive material is accordingly narrowly limited. For determining the optimal point for shattering the grenades into splinters two important conditions are therefore to be taken into account: first the shattering should take place as close as possible to the target, to develop a high effect on the target; in the case of earth and sea targets this means that the grenades must be detonated in the field surrounding the target. To achieve a good striking likelihood for the splinters the shattering must take place at a not too small distance from to the target. The flight time up to the shattering must absolutely be determined so that the shattering occurs before the impact. The mentioned conditions set narrow boundaries for the optimal region of the shattering point and especially for the height range of the shattering point.
Cannons are generally used for the destruction of targets with elongated shots. The trajectories of the projectiles launched in this way are therefore elongated or only slightly elevated and exhibit therefore overall only a small elevation above the ground relative to the attacked target. These projectiles are customarily so programmed that they are detonated at a certain longitudinal distance from the weapon. Because of the elongated flight paths in this case the projectiles detonate at low heights above the target.
Other tube weapons, especially tube weapons in the style of grenade launchers, shoot projectiles or grenades along trajectories which are more strongly elevated or curved than the trajectories of the above-mentioned cannon projectiles. In the case of these projectiles the programming takes place in the same way as with cannon projectiles, so that the programming takes into account the important requirement that the detonation point of a projectile should lie at a definite, small as possible, height above the target.
Indeed different possibilities are known for allowing the projectiles to detonate at an optimal position with the corresponding programming of the projectile taking into account the actual muzzle velocity or the deviation of the actual muzzle velocity from a known muzzle velocity. U.S. Pat. No. 5,814,756 for example describes how the shattering time can be so corrected that the horizontal shattering distance in front of the target remains constant as much possible. Also, U.S. Pat. No. 5,894,102 describes a method for correcting the shattering time for the purpose of maintaining a constant shattering distance between the weapon and the shattering point. Another method for shattering a grenade at a given horizontal distance from the weapon is revealed by U.S. patent application 2002/088367, wherein however no measurement of the muzzle velocity and no programming of the projectile results, but the detonation is triggered by a radar signal. All three mentioned documents therefore describe methods by which detonation of a projectile takes place at a predetermined horizontal distance.
Obviously the disadvantage of using the customary programming method originally designed for the elongated shooting of projectiles, which are shot along heavily curved trajectories, lies in that these projectiles because of their elevated trajectories are not detonated over the target at the optimal height and thereby have no satisfactory effect.
Moreover, in actuality the detonation of the projectiles does not occur at all, or only by chance, at those exact points at which they are supposed to take place according to the programming, since, as already mentioned, for different reasons always a certain scattering occurs. An essential ground for the scattering lies in that the actual muzzle velocities of the projectiles deviate from the theoretically calculated muzzle velocity of the projectiles, with however the programming being made on the basis of the theoretical muzzle velocity.
Summary of the Invention
It is now the object of the invention,                to provide a method by means of which the effectiveness of projectiles, the trajectories of which are not elongated, is improved even if a deviation of the actual muzzle velocity of the projectile from the theoretical muzzle velocity is present;        and to propose a tube weapon with a programming system which is suited to the carrying out of the method.        
The solution to this object in accordance with the invention occurs                for a method; and        for a tube weapon with a programming system.        
In the method, a shattering point in the vicinity of the target is determined by the distance to the target, the adjustment of the tube elevation in accordance with the predetermined muzzle velocity, and an optimal height of the shattering point above the target. The actual muzzle velocity is then determined and a calculation for the programming is carried out taking into consideration the actual muzzle velocity and the optimal height of the shattering point above the target. The programming is then transmitted to the projectile. The tube weapon includes a programming system carrying out the method.
The new method is especially, but not exclusively, used for tube weapons, hereinafter designated as weapons, which are shot in the lower angle group. The projectiles are programmed by the transmission of programming or a corresponding signal. The calculations for the programming take place with reference to the position of the target, launch and terminal ballistic criteria, a predetermined muzzle velocity, an actual or measured muzzle velocity of at least one of the projectiles, and the boundary condition that the detonation should occur at a shattering point which lies at an optimal height above the target.
In a pre-calculation the predetermined theoretical muzzle velocity is used. In a definitive calculation two thoughts are combined, namely the taking into account of the actual muzzle velocity, which is determined by a measurement, and the maintenance of the optimum height of the shattering point.
In this, the precalculation can be carried out before the measurement of the actual muzzle velocity, and after the measurement of the actual muzzle velocity a calculation correction, and with it the ultimate calculation, can be carried out; or the entire ultimate calculation can take place after the determination of the actual muzzle velocity.
With the new method one achieves the shattering of projectiles, such as grenades which are shot along strongly curved trajectories, at an optimal height over the target. The otherwise usual scattering, caused by the deviation of the actual muzzle velocity from the predetermined muzzle velocity, is practicality avoided by taking into consideration the actual or measured muzzle velocity. Taking into account the actual or measured muzzle velocity for optimizing the height of the detonation location is new, since customarily by taking into consideration the actual or measured muzzle velocity, the shot length, that is, the longitudinal distance of the detonation place from the weapon, was optimized.
The new method and the new programming system are, as already mentioned several times, intended especially for tube weapons, for example infantry weapons or machine cannons, which are suited for the shooting of projectiles along strongly curved trajectories and preferably in the lower angle group, wherein the descent angle relative to the horizontal exceeds about 5°.
Generally tube weapons used within the framework of the invention are those which are at least semi-automatic or automatic tube weapons, especially grenade launchers or machine cannons. The programming according to the method of the invention can however, also be carried out for projectiles fired as individual shots.
For the carrying out of the method, a tube weapon with a programming system is used. That programming system has according to the invention v0-measuring means, computing means including memory means for the processing of data for the programming, and transmission means for the transmission of the programming or corresponding signals to the projectiles.
Preferably integrated distance measuring means are provided for measuring the longitudinal distance of the target from the tube weapon. For this however an external distance measuring means can also be used, and in certain cases the mentioned longitudinal distance can also be determined with the help of topographical maps.
The construction of the tube weapon with the programming system is preferably such that the delivery of projectiles is blocked if, as a result of the computations for the programming, a shattering point results which lies within a safety field around the tube weapon. The safety field is essentially dependent on the projectiles or their effective area.
Tube weapons for the delivery of projectiles in serial fire and with the new programming system are preferably so constructed that a serial firing or a firing burst is initiated by a shooter and is continued until an interruption is caused by the shooter.
It is advantageous if upon an interruption of serial fire certain settings are maintained, especially, in case the same target is again to be destroyed, the settings associated with the longitudinal distance of the target. A further serial firing or a further firing burst for destroying the same target can then take place without further input, and only upon the destruction of a new target must the associated settings be changed. The tube weapon can however also be so constructed that at the end of a serial firing or firing burst the used set values are cancelled.